The focus of this project is on understanding the relations between visual function and structural changes in the retina. Extensive structural changes occur naturally in teleost retina. These changes, together with the wide range of techniques that are available in the PI's laboratory to evaluate their effects on vision, will permit refined insights into structure-function relations in the vertebrate retina. The effect on visual function of three general classes of structural change will be studied: changes that occur during development in young animals, changes that are induced by light in adult animals, and changes that occur under the control of circadian clocks. The techniques to be employed include electrophysiological recording (ERG's and retinal ganglion cells), pharmacological manipulations, and retinal morphometry. The project aims to address the following specific questions: 1.How do developmental changes in photoreceptor density influence visual sensitivity? 2.Do retinomotor movements influence visual sensitivity? 3.Where do circadian rhythms in visual sensitivity originate? The significance of the research lies in the explicit acknowledgment that the retina is structurally dynamic, and that retinal dynamics must therefore be considered in the development of current theories of structure-function relations in retina. Studying a naturally dynamic system--the teleost fish retina--will allow new perspectives on the relations between structure and function at the first stages of visual processing.